If you click on “Update Office” accidentally, the Office installation will be upgraded automatically. Therefore, you must disable “Upgrade to Office” notification permanently if you want ...

but newer versions including Office 2013 and Office 365 have their own update system. The message you are seeing is a valid notification, and you should go ahead and install these updates.

In the past, locking the device has prevented Office from being updated. "Update under lock" hopefully alleviates stress on admins whose users are sick of update notifications for Office apps.

When changes have been made in Word, PowerPoint, or Excel, Windows will send you notifications on your mobile phone. Those updates won’t been seen by most Office users yet, however, as they’re ...